The present invention relates to field emission displays, particularly to a junction-based field emission display, and more particularly to a field emission display which utilizes junctions formed by depositing a semiconducting or dielectric, low work function, negative electron affinity (NEA), silicon-based compound film (SBCF) onto a metal substrate or an n-type semiconductor substrate.
Field emission displays traditionally rely on electron emission from arrays of precisely manufactured sharp tips. The ease of electron emission, and therefore the reduction in energy consumption of the display, depends not only on the work functions of the materials used to fabricate the tips but also on the sharpness of the tips. Thus there has been a need for a field emission structure that provides a quick and inexpensive way to reduce drastically the voltages necessary to extract electrodes from the cathodes and to remove completely the requirement of fabricating sharp tips in field emission applications.
The present invention provides a solution to the above-mentioned need by providing a junction-based field emission structure which eliminates the use of sharp tips, reduces the voltages necessary to extract electrons, and provides an inexpensive field emission display. The field emission display of the present invention utilizes junctions formed by depositing a semiconducting or dielectric, low work function, preferably NEA SBCF onto a metal substrate or an n-type semiconductor substrate. A small forward bias voltage is applied across the junction so that electron transport is from the substrate into the SBCF region; and upon entering into this NEA region, many electrons are released into the vacuum adjacent the junction and accelerated toward a positively biased phosphor screen anode, lighting it up for display.
It is an object of the present invention to provide an improved field emission display.
A further object of the invention is to provide a junction-based field emission display.
A further object of the invention is to provide a field emission display which eliminates the use of sharp tips.
Another object of the invention is to provide a device for field emission applications which reduces the voltages necessary to extract electrons from the cathode.
Another object of the invention is to provide a field emission display which utilizes junctions formed by a semiconducting or dielectric, low work function, preferably NEA SBCF onto a metal or n-type semiconductor substrate.
Another object of the invention is to provide a junction-based field emission display using a silicon-based compound (SBC) deposited directly on either an n-type semiconductor or a metal substrate.
Another object of the invention is to provide a field emission device using an SBC, which consists of silicon, oxygen, and an alkali metal deposited on a metal or n-type semiconductor substrate.
Another object of the invention is to provide a junction-based field emission display wherein a small forward bias voltage is applied across the junction so that electron transport is from a substrate into an SBC causing release of electrons which are accelerated toward a positively biased phosphor screen anode.
Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings. Broadly, the present invention is a junction-based field emission structure which provides a quick and inexpensive way to reduce drastically the voltages necessary to extract electrons from the cathode and to remove completely the requirement of fabricating sharp tips in field emission applications. The junction-based field emission device uses a semiconducting or dielectric and NEA SBCF deposited directly onto either an n-type semiconductor or a metal substrate. The SBCF can be doped to become a p-type semiconductor. The SBCF consists of silicon, oxygen, and an alkali metal, such as Cs or Ba, and is synthesized by the techniques of thermal vaporization and pulsed laser deposition. To light up a phosphor screen of a field emission display, such as a flat panel display, a forward bias voltage is applied across the junction so that electrons flow from the substrates into the SBCF region, and due to the NEA property of this region, many electrons immediately escape to the vacuum level and are accelerated toward the positively biased phosphor screen anode plate to light it up for display. To turn off the screen, simply switch off the applied voltage across the junction.